diff -urN v4/ezhtml.py v5/ezhtml.py
--- v4/ezhtml.py	2018-09-17 23:46:44.000000000 +0900
+++ v5/ezhtml.py	2018-09-18 00:31:27.000000000 +0900
@@ -130,6 +130,18 @@
 		o = o[0]
 	return o
 
+def yaml_dump(o):
+	def represent_str(dumper, instance):
+		tag = 'tag:yaml.org,2002:str'
+		style = '|' if '\n' in instance else None
+		return dumper.represent_scalar( tag, instance, style=style )
+
+	for typ in [ str ] + ( [ unicode ] if six.PY2 else [] ):
+		yaml.add_representer(typ, represent_str)
+
+	u8 = yaml.dump( o, default_flow_style=False, allow_unicode=True, encoding='utf-8' )
+	return nkf.dec(u8)	
+
 if __name__ == "__main__":
 	b = nkf.get_stdin()
 	opt = nkf.guess(b)
@@ -139,7 +151,7 @@
 
 	if html:
 		o = html_load(s)
-		s = yaml.dump( o, default_flow_style=False )
+		s = yaml_dump(o)
 	else:
 		o = yaml.load(s)
 		s = html_dump(o) + '\n'